Hydrogenization and dehydrogenization of carbon compounds.



UNITED STATES PATENT OFFICE.

CARL BOSCH, ALWIN MITTASCH, AND CARL KRAUCH, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSIGNORS TO BADISCHE ANILIN & SODA FABRIK, 0F LUDWIGSHAFEN-ON -THE-RHIN E, GERMANY, A CORPORATION.

HYDROGENIZATION AND DEHYDROGENIZATION OF CARBON COMPOUNDS.

No Drawing.

To all whom it may concern.

Be it known that We, CARL Boson, ALwIN MrrTAsoH, and CARL KRAUCH,citlzens of the German Empire, residing at Ludwigshafen-on-the-Rhine,Germany, have invented new and useful Improvements in theHydrogenization and Dehydrogenization of Carbon Compounds, of which thefollowing is a specification.

Our invention relates to the hydrogenization and dehydrogenization inthe presence of a catalytic agent of compounds containing carbon, and tocatalytic mixtures by means of which the said hydrogenization anddehydrogenization can be carried out rapidly, with certainty and atcomparatively low temperatures. We have discovered that these advantagescan be obtained by employing as the catalytic agent an intimate mixtureof a common metal, in particular iron, nickel, cobalt and copper (whichwe hereinafter refer to as the catalytic metal), with a precipitateddilficultly reducible oxygen-containing compound of a metal which iscapable of forming only a weak basic oxid. In particular We mention theoxide and oxygen-containing salts of the earth metals, lncludin the rareearths, (see Zeitschm'ft fair Ele trochemz'e, vol. 17, p. 633), and ofberyllium, magnesium, manganese, uranium, vanadium, columbium, tantalum,chromium and titanium. All of these oxygen-containing compounds whichpromote the activity of the catalytic metal, we refer to hereinafter aspromoters.

In order to obtain the advantages of this invention it is necessary toeffect an intimate mixture of the catalytic metal and the promoter, andit is not sufiicient merely to fill the components, for instance nickeland alumina, side by side, into the reaction space. For instance, goodresults can be obtained by precipitating the hydroxids, oxids orcarbonates of the components together from a solution contalnin saltsthereof; or ,mixtures of the said sa ts, for instance, the nitrates ofthe components can be heated until a molten condition is obtained.Further, the mixture can be obtained, although not always with equalcertainty and excellence, by mechanical o erations, such as grindintogether as fine y as possible, or by knea ing in a moist state.

Specification of Letters Patent.

Patented July 2, 1918.

Application filed June 4, 1914. Serial No. 842,955.

If necessary, the mixture is subsequently heated and reduced so that inevery case the catalytic metal, that is to say iron, nickel, cobalt orcopper, is obtained in a metallic condition, while the promoter alwaysretains more or less oxygen. When the promoter is to consist of aninsoluble oxid such, for instance, as aluminium oxid and titanium mod,it is preferred to start from a soluble compound thereof, and toprecipitate the insoluble oxid on the catalytic metal, or on thecompound from which the catalytic metal is to be prepared. For instance,if aluminium acetate be employed to yield the promoter, namely aluminiumoxid, the said acetate can be merely heated in the presence of thecatalytic metal or compound thereof, so that the acetic acid is drivenoff, or decomposed, and the alumina remains. If insoluble salts, suchfor instance, as chromates be employed as promoters, these are referablybrought into intimate mixture with the compound which is subsequently togive rise to the metallic catalytic agent, by precipitation fromsolutions of suitable soluble salts or other compounds. The salts whichact as promoters may contain the oxid to which the promoting action isascribed either in the acid, or in the basic constituent, or in both theacid and the basic constituent. We mention, calcium aluminate, aluminiumphosphate and magnesium aluminate as instances of these three types.

It is particularly advantageous for the purpose of preparing a veryactive contact mass to prepare, at least the catalytic metal, fromcarbonaceous salts or mixtures of salts thereof, for instance, fromcarbonates or from formates. The action of the catalytic mixture canfurther often be increased by adding an alkali metal compound, forinstance, caustic soda; even traces of such compounds have often afavorable action. It is further often useful to add to the mixture,bodies of inorganic or organic nature, which act either as carriers, oras binding agents, or which increase the porosity of the contact mass.We mention, for instance, asbestos charcoal and pumice. It is advisablehowever, to avoid the introduction of bodies such as chlorin, sulfur,arsenic and lead, which may in the elementary form act as contactpoisons, although the new contact mixtures according to thepresentinvention,

are not so sensitive to the action of poisons as are the pure metals. Itis consequently possible to employ as a promoter, a salt which containsone of the poisonous elements, but in which the poisonous action iscounteracted by the promotin influence of the oxid; for instance, basica uminium sulfate possesses a strong promoting action. The catalyticmetal can be employed either in a state of fine division, or in a morecompact form, such as wire netting, or wool, or in sheet form.

Instead of employing only one of the above mentioned oxids, or otheroxygen compounds, a mixture of two or more may be added to the catalyticmetal.

The proportion of the components employed in the catalytic mixture maybe considerably varied, even an addition of one per cent. or less of thesaid promoters often producin favorable action. It is generally preferrehowever, to add larger quantlties of the promoter, say from ten totwenty per cent. or even more.

In those cases in which reduction has to be resorted to in order toobtain the catalytic metal, such reduction is preferably carried out bymeans of pure hydrogen or other suitable agent at as low a temperatureas possible, and if the catalytic mixture, after having been reducedwith hydrogen, has to be exposed to the air, it is generally advisablepreviously to drive away any excess of hydrogen by passing anindifferent gas such as carbon dioxid over the mixture and thus avoideven superficial oxidation of the metal.

The catalytic mixtures according to this I invention can be used for thehydrogenization and dehydrogenization of compounds containing carbon andof particular value for the hardening of fats and fatty acids, but theycan also be used for other purposes, for instance, for converting phenolinto cyclohexanol and for reducing nitrobenzene to anilin, and for theconversion of oxids of carbon into hydrocarbons.

The catalytic reaction according to this invention can be carried outeither at ordinary pressure or under increased pressure, for instance,above 50 atmospheres, and in most cases proceeds sufficiently rapidly attemperatures considerably below 180 C.

The process of the present invention is of great importance. It hasindeed been pro posed'to employ mixtures of metallic nickel and the likewith sodium hydrate, sodium chlorid, barium chlorid, sodium nitrate andsodium sulfate, for the catalytic dehydrogenization of variouscompounds; the action of such mixtures is, however, relatively smallcompared with that of the mixtures according to the present invention,and moreover, the employment of strong bases is often detrimental, forinstance, in the case of hydrogenization of fats, since they tend tosaponify the fats, and very soon disappear from the contact mass. On theother hand, when employing promoters according to our invention, that isto say, promoters which have not a strong basic action, contact massesare obtained which are characterized by a strong and more or lesspermanent action. Of course, for different processes of hydrogenizationand dehydrogenization according to this invention, dlfl'erent mixture ofcatalytic metals and promoters may be preferred in particular cases.

The followin examples will serve to illustrate further t e nature ofthis invention, which, however, is not confined to these examples. Theparts are by weight.

Example 1.

Dissolve a mixture of 15 parts of nickel nitrate and 1 part of berylliumnitrate, precipitate while hot with soda, filter off the precipitate,and wash and dry it. Then at a temperature of 250-300 C. pass a mixtureof gases containing one volume of carbon monoxid and three volumes ofhydrogen over the mixture until the reduction of the nickel oxid iscomplete, and the conversion of the carbon monoxid into methane istaking place. The temperature can then be re duced to about 150 C. oreven less without the catalytic agent becoming inactive. If desired, theentire reduction of the nickel oxid can be carried out with purehydrogen. The precipitation can, for instance, be carried out by meansof alkali hydroxid. Instead of beryllium nitrate, zirconium nitrate orthorium nitrate, can be employed.

E trample 23.

Pour an aqueous solution of 1 part of aluminium nitrate over 5 parts ofnickel oxalate, evaporate the mixture and dry and reduce it in a currentof hydrogen at from 300350 G.

Then introduce the nickel containing alumina, while excluding air, intoa shaking vessel provided with a stirrer, the said vessel containin fishoil or other suitable oil, which may ave been previously purified. Ontreatment with hydrogen at, for instance, 100 0., hydrogenization takesplace considerably more rapidly than if pure nickel were employed as thecatalytic agent. Instead of aluminium nitrate, cerium nitrate or ceriumammonium nitrate can be employed.

E wample 3.

Precipitate a hot solution containing nickel nitrate and aluminiumnitrate with potassium carbonate, wash the precipitate, dry it, heat itto 300 C. and reduce it with hydrogen. Then place the catalytic mixturewith soy bean 011 in an autoclave, while avoiding the presence of air,heat to 80 C. and allow hydrogen to act at a. pressure of twentyatmospheres while suitably mixing the constituents.

The hydrogenization takes place very rapidly. If desired the pressurecan be increased, for instance, up to 50 atmospheres, or higher. In thisexample, if iron nitrate be employed instead of nickel nitrate, goodresults can be obtained. The reduction to metallic nickel or iron can becarried out in the autoclave itself, for instance, at 250300 C. and 80atmospheres pressure.

Example 4. Mix 13 parts of nickel hydroxid with 2 parts of magnesiumhydroxid, and warm soda, then filter, wash,

them gently with concentrated formic acid which is free from sulfur,until the formates are obtained. Heat the mixture gentl and then treatwith hydrogen at 300 On treating olive oil with hydrogen in the resenceof this catalytic mixture at say rom 80-100 C. a more rapidhydrogenization is brought about than is the case when ure nickel isused. In this example the hy roxids can be replaced by the correspondingcarbonates if desired, and carriers for instance, pieces of clay can beem loyed, these beingsoaked in a melt or solution of nickel salts,preferably of the soluble double salts, such as nickel ammonium formateor ammoniacal nickel carbonate solution, together with the promoter, andthen treated as hereinbeforc described.

Ewampl 5.

Bring nickel wire netting into the form of loose spheres, rolls or thelike, and clean these with pure dilute nitric acid, then wash them andmoisten with a moderately concentrated solution of aluminium nitrate,then dry and treat with hydrogen at from 300- alumina can, for instance,be employed for the hydrogenization of linseed oil, which can be allowedto trickle over the catalytic agent while the hydrogen is supplied, anda con siderable or even complete hardening is effected.

Example 6.

Dissolve 85 parts of nickel nitrate and 15 parts of titanium lactate ina small quantity of hot water and preci ry and reduce with hydrogen at300 C. add the catalytic mixture containing titanium-oxid to cotton seedoil, and then treat with hydrogen at from 100120 C. while maintainingthe mixture in a state, of motion.

If desired, the reaction can be carried out under increased pressure,for instan e, 100 atmospheres, and in this case the hy rogenizationtakes place very rapidly and completely even at a temperature of 90C.'or

itate by means of,

pounds containing carbon b i 'Emaamp le 7'.

Add 2 parts of dissolved potassium aluminate to a solution containing 30parts of nickel nitrate and 1% parts of calcium nitrate and introducethe whole into a boiling solution of sodium carbonate. Then filter, washwell, dry and reduce. The nickel catal ti agent containing calciumaluminate can tie employed for hydrogenization purposes, for instance,into an oil resulting from cracking petroleum residues and which is richin unsaturated compounds, whereupon hydrogen is allowed to react at atemperature of 100 C. and at a pressure of '80 atmospheres. The iodinnumber is rapidly reduced and at the same time the color and unpleasantodor diminish.

In a similar manner other contact mixtures can be employed, whichcontain as a promotor, for instance, calcium vanadate, barium chromateand barium tungstate, or the compounds which result by the reduction ofthese compounds.

Now what we claim is 1. The process of hydrogenizing com poundscontaining carbon by tre ting such compounds with hydrogen 1nd: epresence of a heated intimate mixture of a common metal actin as acatalyzer for the said reactions, and a precipitated diilicultlreducible oxygen-containing compound 0 a metal which is capable offorming only a weak basic oxid.

2. The process of hydrogenizing compounds containing carbon by treatingsuch compounds with hydrogen in the presence of a heated intimatemixture of a metal of the iron group and a precipitated difiicultlreducible oxygencontaining compoun it may be introduced which is capableof forming only a weak basi oxid.

3. The process of hydrogenizing comcompounds wlth hydrogen in thepresence of a heated intimate mixture of nickel and a precipitateddiflicultly reducible oxy en-containing compound of a, metal whic iscapable of forming only a weakbasic oxid.

4. The process of treating such compounds with hydrogen in the presenceof a heated intimate mixture of nickel and a precipitated oxygencontaining compound of aluminium.

5. The process of hydrogenizing com-- pounds containing carbon bytreating such hydrogenizing com-.

of a common metal acting compounds with hydrogen in the presence of aheated intimate mixture of nickel and aluminium oxid prepared byprecipitation.

6. The process of hydrogenizing compounds containing carbon by treatingsuch compounds with hydrogen under a pressure exceeding that of '50atmospheres, in the presence of a heated intimate mixture of a commonmetal and a precipitated diificultly reducible oxygen-containingcompound of a metal which s capable of forming onlyla weak basic oxid.

a weak basic oxid.

8. A catalyst comprising co-precipitated nickel and "a diflicultlyreducible oxygen comound of a metal which is capable of formmg only aweak basic oxid, said nickel having the catalytic powers of nickelreduced at temperatures around 300 C.

9. A catal st comprising co-precipitated nickel and ai umina, saidnickel having the catalytic powers of nickel reduced at temperaturesaround 300 C.

In testimony whereof we have hereunto set our hands in the presence oftwo subscribing witnesses.

OARLBOSCH. v. ALWIN MITTASCH. CARL KRAUCH.

Witnesses:

On. Tnunomnn, J. Ame. Lnoro.

